Electromagnetic relay



Feb. 26, 1935. E. J. GACHET 1,992,610

ELECTROMAGNETIC RELAY Filed Nov. 1, 1953 [/VVL-NTOR- ERA/EST Jaws GACHET Arr): I

Patented Feb. 26, l935 UNITED STATES ELECTROMAGNETIC RELAY 7 Ernest Jules Gachet, London, England, assignor to Siemens Brothers & Company Limited, London, England Application November 1, 1933, Serial No. 696,132

In Great Britain December 2, 1932 1 Claims. (01. 175-336) This invention relates'to'improvements in electromagnetic relays and more particularly to the kind in which the armature is secured to a flat I spring which is tensioned so as to hold a partoi the armature against a part of the relay core leaving a small air gap between the armature and a pole face of the relay core.

Such a relay may have very precise and fast operating and releasing characteristics, and owing to the lightness and resilient mounting of the armature there is a liability to contact bounce, this liability being increased the quicker the relay operates. Contact bounce is very undesirable as in effect it increases the time of operation and release of the contacts. Furthermore there is a possibility that the spring may be caused to vibrate at its natural frequency or at a harmonic thereof and if the relay is to be used,

as a vibrator, such as for a tone generator, the springmay vibrate in response to a harmonic of its natural frequency bringing about contact chattera In such relays heretofore the spring carrying the armature has been adjusted and tensioned by a force directly applied to the spring by an adjusting screw bearing on the spring.

In the present invention the tension adjusting .various items of the relay, and extensions of member does not operate directly on the spring carrying the armature but through an intermediate spring which acts on the armature spring betweenthe two points of support of the latter spring. With advantage the intermediate spring may be arranged so that not only one part bears on the armature spring as mentioned but an other part acts directly to keep the armature spring on the limb of the magnetic system mentioned. The provision of an intermediate spring carries with it certain advantages above the case where a tension adjusting screw acts directly, such as flne adjustment, less necessity for carefully positioning, and shaping the end of the tension adjusting screw.

A convenient form of intermediate part is a spring which is bent and slotted so that the armature spring passes through it at one place, one end being fixed at the same place as the armature spring but on one side of it and the other end bearing on the other side of the armature spring at the fulcrum point of the armature. 50 The tension adjusting screw, bears intermediately between the fulcrum point and the place where the armature spring passes through. By these means the tensioning screw is adapted to cause pressure to be exerted on the armature spring at the fulcrum point and where the armature spring passes through this intermediate spring part.

The armature spring which carries the moving contacts of the relay may be stiffened by channelling or grooving at its contact carrying end 5 and it may be slotted to reduce its inertia and windage.

The armature may be spot welded to the spring.

The invention will be more fully understood from the following description taken in conjunction with the accompanying drawing wherein Fig. 1 illustrates a plan view of a relay incorporating the features of the present invention, Fig. 2 illustrates an end view of the armature spring carrying the armature, and Fig. 3 a side elevational view of the relay.

The component parts of the relay are mounted on a, metal baseplate l which is bent at rightangles to form a letter L the short limb being secured by screws 2 to the mounting plate 3. The long limb of the baseplate is provided with a lug 28 bent into a plane at rightangles to both the limbs. The lug 28 supports the wiring tags 21 which are insulated from each other and are secured to the lug 28 by the screws 22. Wiring connections are made from these tags to the the tags extend through the mounting plate 3 for the termination of the external wiring.

Secured to the inner surface of the long limb of the baseplate 1 by the screws 5 is a plate 4 of insulating material preferably that known under the registered name Bakelite.

On the plate 4 is supported a yoke 6 of soft iron which is secured to the plate by the screws 7, the heads of which screws are sunk into clearance apertures inthe baseplate 1 and engage with the underside of the plate 4. The yoke 6 15 provided with lugs 8 and 10, the lug 10 being bent at rightangles to the body of the yoke 6 and to the long limb of the baseplate 1 to support the armature spring 11 and a further spring 20 both of which are secured to the lug by screws, a soldering connecting tag in contact with the springs also being secured by the screws. The lug 8 also, stands out at rightangles to the body of the yoke 6, the end of the lug 8 being bent over upon itself to form a U, a thumb adjusting screw 9 engaging with the limbs of the U and adapted to register at its free end with the further spring 23.

The end of the yoke 6,-opposite the end from which the lug 10 projects, is first-cut out and formed with a piece 29'thereof at rightangles to the body of the yoke, somewhat in the form of a letter T, the cross limb 30 on one side of the body however, being out almost flush with the corresponding side of the body while the limb 31 projecting from the other side of the body is bent round to form a letter U so that the, end faces of the cross piece lie approximately in the same plane. The body is then bent upward at rightangles to itself so that the limbs of the U cross piece lie approximately parallel to the body of the yoke. This U-piece forms the core 27 of the relay, and the end faces are the pole faces.-

The limb of the U-piece 27 is enclosed by a magnetizing coil 24 wound on a bobbin, the bobbin being securely wedged on the limb of the U by a brass strip interposed between the inside of the bobbin and the limb, the ends of the brass strip being turned up to embrace the bobbin and the core.

Obviously, a further magnetizing coil could be placed on the other limb, or over the whole coil.

The armature spring 11 secured at one end to the lug 10 as previously described, is mounted so as to lie with its breadth parallel to and across the pole faces 27 and of the U piece of the yoke 6. the armature 12 of soft iron, preferably coated with a non-magnetic material, being secured by riveting or spot welding to the spring adjacent the pole faces. The spring 11 along a portion of its length and near its free end is slightly broadened and has its edges turned over to make the spring channel shaped along this portion, as illustrated in Fig. 2. This end of the spring may be provided with an aperture such as shown at 19 to reduce the mass and consequently the inertia. The free end of the spring 11 is provided with contact points 13 adapted to contact with one or other of the contacting ends of the contact screws 14 and 15 when the relay is unoperated and operated respectively. These screws 14 and 15 are mounted in rightangled brackets, such as 16, secured to the plate 4 by screws, such as 17. Soldering tags 18 are clamped beneath the brackets and a further thin sheet of white insulating material may be placed between plate 4 and the brackets and beneath the contact points so that the adjustment of these and the armature gap may be observed. The limbs of the brackets through which the contact screws pass maybe split and the adjustment of the contact' screws preserved by tightening the halves of the split ends together by screws such as 26.

The further contact spring 20, is secured to the lug 10 together with the spring .11, and is secured on the same side of the, spring 11 to which the armature 12 is attached. The spring 20 is broader than the spring 11 and is first bent away from the'spring 11, and is provided with an aperture through which the spring 11 is passed to admit of the diagonal crossing of the spring 20 past the spring 11 to the other side thereof where the spring 20 is again bent to lie approximately parallel with the spring 11. The end of the spring 20 is curved to bear on the spring 11 at a place above the limb 30 of the magnet core 2'7.

The spring 20 passes in front of the'end of the adjusting screw 9, and this screw is adjustable to cause the spring 20 to press onto the armature spring 11 in two places, these places being at one side of the aperture in the spring 20 and at the end thereof adjacent the first pole face 30 about which the armature pivots so that the end of the armature 12 is maintainedv in contact with the first pole face ,30. The screw 9 is held against rotation due to vibration by the frictional en gagement therewith of spring 23 secured in with the block of connecting tags 21 and registering with the roughened underside of the head of the screw. The provision of the intermediate spring 20, enables the adjusting screw 9 to be provided with a comparatively coarse thread thus cheapening the production costs of the screw.

For the electrical connections wires are interconnected between the block of connecting tags 21 and the soldering tags in connection with the various items, such as the tags 18 and the tags in connection with the springs 11 and 20.

It will be appreciated that by the use of the spring 20 the possibility of "twist" being imparted to armature spring 11 by fortuitous incorrect registration of the adjusting screw 9 therewith is considerably reduced, this being a distinct advantage where the relays are manufactured by a mass production process.

The operation of the relay is as follows; on the energization of the coil 24 the U piece of the yoke is magnetized and the armature 12 which pivots about the first pole face 30 is attracted towards the secondpoleface 27, the armature spring 11 between the armature and bracket 10 bowing, while the contacts 13 leave the contact screw 14 and connect with the contact screw 15, the spring 11 restoring when the coil 24 is de-energized.

It will be seen that the spring 20 bearing at a suitable place along the length of the armature spring 11 serves to damp the spring against vibration. The point where the armature spring passes through the aperture in the spring 20 is preferably so chosen that the tension in the spring 11 is applied at a place such that the armature spring is divided into lengths the natural frequencies of which are not related in any simple multiples of one another, thereby reducing the tendency of the spring to vibrate in any of its more prominent harmonics.

I claim:-

1. In an electromagnetic relay, an armature and a core, a bearing spring fixed at one end for securing said armature, said bearing spring tensioned to hold one end of said armature against one end of said core and leave a small air gap between the armature and the opposite end of said core. adjusting means for adjusting the tension of said bearing spring, and an intermediate spring acted upon by said adjusting means engaging said bearing spring at a point between its fixed end and the first end of said core.

2. In an electromagnetic relay, an armature and a core, a bearing spring fixed at one end and having the armature secured at the other end.

.said bearing spring tensioned to pivot said armature on one end of said core and to leave an air gap between the armature and the other end of said core, adjusting means for adjusting the tension of said bearing spring, and an intermediate spring acted on by said adjusting means to exert pressure on said bearing spring at the point where said bearing spring is pivoted on said core.

3. In an electromagnetic relay, a U-shaped core, a bearing spring, an armature secured to said bearing spring in a position across the ends of said core, an intermediate spring having one end engaging said bearing spring to pivot said armature on one end of said core, means for supporting both of said springs, and adjusting means engaging said intermediate spring.

4. In an electromagnetic relay, a U-shaped core, a bearing spring,.an armature secured to said bearing spring in a position across the ends of said core, an intermediate spring having one v end engaging saidbearing spring to pivot said armature on one end of said core, means for supporting both of said springs, and adjusting means engaging said intermediate spring at a point midway of said spring supporting means and the pivot point of said armature.

5. In an electromagnetic relay, a U-shaped core, a bearing spring, an armature secured to said bearing spring in a position across the ends of said core, an intermediate spring having one end engaging saidbearing spring to pivot said armature on one end of said core, means for supporting both of said springs, and adjusting means engaging said intermediate spring at a point midway of said spring supporting means and the pivot point of said armature, and contact points fixed on said bearing spring.

6. In an electromagnetic relay, a core, a hearing spring, an armature supported by said hearing spring and positioned opposite the end'of said core, an intermediate spring engaging said bearing spring to pivot said armature on one end of said core, common means for supporting both of said springs with said intermediate spring on one side of said bearing spring, said intermediate spring shaped so as to engage said bearing spring on the opposite side, and an adjusting means engaging said intermediate spring on said opposite side of the bearing spring and on the same side where said intermediate spring pivots said armature.

7. In an electromagnetic relay, a core, a bearing spring, an armature fixed to said bearing spring to position it opposite the end of said core, an intermediate spring engaging said bearing spring on one side to pivot the armature at the end of said core, common means for supporting both of said springs so said intermediate spring is on the opposite side of the bearing spring from where it pivots said armature, said intermediate spring having an opening therein through which said bearing spring extends, and adjusting means engaging said intermediate spring on the said side that it engages said bearing spring.

8. In an electromagnetic relay, a U-shaped core, a bearing spring, an armature secured to said bearing spring in a position across the ends oi said core, an intermediate spring having one end engaging said bearing spring to pivot said armature on one end of said core, means for sup-. porting both of said springs, and adjusting means engaging said intermediate spring at a point midway of said spring supporting means and the pivot point of said armature and at a point along the length of said bearing spring so that it is divided into sections the natural frequencies of whichare not related in any simple multiples of each other.

9. In an armature spring for electromagnetic relays, an armature fixed to said armature spring, an intermediate spring engaging said one side of said armature spring for pivoting said armature, said intermediate spring passing to the other side of said armature spring, common means for supporting both of said springs, and adjusting means engaging said intermediate spring on said first side of said bearing spring and at a point between the armature pivoting point and said spring supporting means.

10. In an armature spring for electromagnetic relays, an armature fixed to said armature spring, an intermediate spring engaging said one side of said armature spring for pivoting said armature, said intermediate spring passing to the other side of said armature spring, common means ior supporting both of said springs, and adjusting means 

